1. Field of the Invention
The present invention relates to a data processing system constructed of an external storage medium for previously storing a program, and also an electronic apparatus capable of connecting the external storage medium and performing the program stored therein.
2. Description of the Prior Art
Very recently, there are commercially available such compact information processing apparatuses that an external storage medium, for instance, an IC (integrated circuit) card is connectable to an apparatus body, under which a program previously stored in the IC card can be executed.
In case that an optional software previously stored in the IC card is used in such an information processing apparatus, a work area, normally a random access memory (RAM) is required to perform the software process. Accordingly, apparatus has been developed where a work area exclusively used for each IC card is employed inside the information processing apparatus body, a work area commonly used for a software of each IC card is provided within the information processing apparatus, and, another work area used to process software is formed inside the IC card.
However, one conventional information processing apparatus in which the memory (RAM) employed therein has been allocated as work areas exclusively used for the respective IC cards (namely, exclusively used for processing the softwares of the respective IC cards), has such a drawback that the utilization efficiency of RAM is lowered since the work area cannot be used for processing any software other than the previously designated software. In another conventional information processing apparatus in which the work areas commonly employed for the respective IC cards have been provided, the memory data may be destroyed when a different software is executed by substituting the present IC card with another IC card. To avoid such a problem, contents of the common memory are once cleared before executing the software of the different IC card. However, this clear operation may require complex manipulation, and also may impede easy operations. For instance, even when the same IC card is loaded, the contents of the common memory are subjected to be cleared, so that the software process cannot be continued while maintaining the previous operating condition. Furthermore, the cost of the conventional IC card where RAM has been employed as the work area is rather expensive, in view of economical reasons.